Fire Weather Tools

Name Inputs Outputs Description Application Map Link

Low Occurrence Risk Relative , smoke dispersion 1 (low chance of low visibility) - 10 (high chance of low visibility) Index for probabilities of low Used in planning prescribed Index (LVORI) index visibility occurring. Extreme burns and nighttime burning. caution is required when the forecast LVORI is 8, 9, or 10 for the nighttime period, as will mix with smoke. Dispersion Index (ADI) Stability, mixing height, transport >100 Very Good (but may indirectly indicate hazardous conditions) Dispersion is the process by which Assess the impact of 61-100 Good (typical-case burning weather values are in this range) the mixes and prescribed burning activity 41-60 Generally Good ( afternoon values in most inland forested areas of the US fall in this range) transports particles such as and on atmospheric 21-40 Fair ( stagnation may be indicated if accompanied by persistent low windspeeds) smoke away from their source. smoke concentrations and 13-20 Generally Poor; stagnation if persistent (although better than average for a night value) Typical burning values are in the air quality. Maximum 75, 7-12 Poor; stagnant at day (but near or above average at night) 1-6 Very Poor (very frequent at night) range 40-60. Hazardous minimum 30 for daytime conditions may exist for ADI > prescribed burning. 100. Should not be used alone in Nighttime minimum 6. making burning decisions . (Florida Values / NC ?)

Haines Index Atmospheric sounding data 2 - 3 very low growth potential Judges the growth potential of a Indicates where wildfires or 4 low potential fire by measuring the dryness and prescribed fires may get out 5 moderate potential stability of the air over a fire. of control. 6 high potential for large fire growth Correlated with large fire growth on initiating and existing fires where surface winds do not dominate fire behavior.

Lightning Activity Level (LAL) Surface Observations, Info from LAL 1 – No . LAL is a measure of the amount of Used to assist in assessing weatehr Balloons, Satelite and LAL 2 – Isolated thunderstorms. Light rain will occasionally reach the ground. lightning activity using values 1 to the potential for lightning is very infrequent, 1-5 to ground strikes in a 5 minute period. 6 caused fires radar images, as well as forecasted LAL 3 – Widely scattered thunderstorms. Light to moderate rain will reach the ground. models. Lightning is infrequent, 6-10 cloud to ground strikes in a 5 minute period. LAL 4 – Scattered thunderstorms. Moderate rain is commonly produced. Lightning is frequent, 11-15 cloud to ground strikes in a 5 minute period. LAL 5 – Numerous thunderstorms. Rainfall is moderate to heavy. Lightning is frequent and intense, greater than 15 cloud to ground strikes in a 5 minute period. LAL 6 – Same as LAL 3 except thunderstorms are dry (no rain reaches the ground). This type of lightning has the potential for extreme fire activity and is normally highlighted in fire weather forecasts with a Red Flag Warning.

Spot Weather Forecast Indicates where wildfires or prescribed Hourly , relative humidity, speed and direction. Special weather forecast issued to Use for prescribed fires and fires may get out of control. Should be fit the time, topography and wildfires. considered along with a surface fire weather for a specific fire. danger index for maximum effectiveness.